My whole family have Caberg helmets, all Justissimo flip fronts, I think I now have 6 of them in the house. They are a good enough and reasonably priced helmet with the built in 'pilots' dark visor that pops down at the flick of a switch. Can be worn as a full face flip, or the face can be removed and worn as an open face helmet, still with the twin visors, full size clear and small 'pilots'.
Down side is the extra wind noise you get when travelling at high speed, but pretty much the same with any flip helmet. A pain to take apart to clean.
Good points are, single button opening flip, front vent, large top vent and the excellent built in sunshade, removable face. Excellent value for money and very very versatile.
I tried and tested mine in full face mode a while back, came off and landed on my chin. First off in 32 years, so will never ever go open face again. The helmet did a wonderful job of saving my face and head, or I would still be sipping my whisky through a straw.
If it helps, the Justissimo flip sells in the UK at £149, the J1 flip without the pilots visor at £99 and the Demi Jet you refer to is also known as the 'Downtown' and has the twin visor system for £80.